PROJECT SUMMARY/ABSTRACT The primary objective of the proposed project is to describe relationships among minority stress, body image distress, impulsivity, and use of substances/alcohol and non-prescription testosterone among transgender female-to-male (FTM) persons. FTMs are male-identified individuals who were assigned female sex at birth. Substance use is a substantial public health risk among FTMs, with FTMs reporting elevated use of substances and alcohol. As well, some FTMs may use non-prescription testosterone to achieve a level of muscularity surpassing what could be obtained by use of prescription doses of testosterone. Transgender FTMs may be at risk for experiencing minority stress and body image distress. Minority stress and body image distress may contribute to transgender FTMs substances/alcohol use to cope with stress, and non-prescription testosterone use to alter their body to a more masculine presentation. As well, impulsivity has been implicated as a moderator of relationship between general stress and use of substances/alcohol such that individuals with higher levels of impulsivity are more likely to use and abuse substances/alcohol compared to those low in impulsivity. Thus, impulsivity may moderate the links between minority stress and body image distress, and substance/alcohol and non-prescription testosterone use, such that higher levels of impulsivity in the context of minority stress and body image distress are associated with increased use of substances/alcohol and testosterone. The aims of the proposed research are to (1) describe the association between minority stress and body image distress, and substance/alcohol use among transgender FTMs and assess whether this relationship is moderated by impulsivity, (2) describe the association between minority stress and body image distress, and non-prescription testosterone use among transgender FTMs and assess whether this relationship is moderated by impulsivity, and (3) describe the relationship between substance/alcohol use and non- prescription testosterone use among transgender FTMs. Results of the proposed research can help to inform future research and interventions focused on substance/alcohol use and use of non-prescription testosterone among this population.